 /*******************************************************************************
  * Copyright (c) 2006, 2007 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.core.databinding.observable;

 /**
  * Generic event denoting that the state of an {@link IObservable} object is
  * about to change. Note that this event is only fired when an observable
  * becomes stale, not when it becomes unstale; an observable that becomes
  * unstale should always fire a change event. Staleness can be used (for
  * example) to notify listeners when an observable has started a background
  * thread for updating its state. Clients can safely ignore staleness.
  *
  * @see IObservable#isStale()
  *
  * @since 1.0
  *
  */
 public class StaleEvent extends ObservableEvent {

     /**
      * Creates a new stale event.
      *
      * @param source
      * the source observable
      */
     public StaleEvent(IObservable source) {
         super(source);
     }

     /**
      *
      */
     private static final long serialVersionUID = 3491012225431471077L;

     static final Object TYPE = new Object ();

     protected void dispatch(IObservablesListener listener) {
         ((IStaleListener) listener).handleStale(this);
     }

     protected Object getListenerType() {
         return TYPE;
     }

 }

